Diego de Landa calls the fiber (kapok) of the Ceiba tree "silk."
Diego de Landa, Yucatan Before and After the Conquest, translated by William Gates (Baltimore, Md.: The Maya Society, 1937, 2011), 119, 123
There are colors of many kinds made from the juices of certain trees and flowers, but because the Indians have not known how to perfect them by gums to temper them in prevention, they fade. But those who gather the silk have already discovered the remedies, and say that they give as perfect results as anywhere found. . . . Hens, pigeons, oranges, limes, citrons, grapes, pomegranates, figs, guavas, dates and bananas, melons and the other legumes; of these only the melons and calabashes grow from their own seeds; for the rest one must bring fresh seeds from Mexico, Silk is now produced, and it is very good. They have received tools, and the use of mechanical devices, and these go well. There is also the use of money and many other things that have come to them from Spain; and although they had gone, and could have gone on without them, yet they live beyond questions more as men by having them and their aid in their corporeal activities, and the raising of them; as, by the opinion of the philosopher, art aids nature.